A5002886797- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Atmospheric chemistry and aerosols
- Spectroscopy and Laser Applications
- Planetary Science and Exploration
- Space Science and Extraterrestrial Life
- Atomic and Subatomic Physics Research
- Analytical Chemistry and Chromatography
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Fullerene Chemistry and Applications
- Advanced Combustion Engine Technologies
- Space Exploration and Technology
- Astronomy and Astrophysical Research
- High-pressure geophysics and materials
- Dark Matter and Cosmic Phenomena
- Various Chemistry Research Topics
- Solar and Space Plasma Dynamics
University of Virginia
2020-2024
National Radio Astronomy Observatory
2021
Max Planck Institute for Extraterrestrial Physics
2021
Smithsonian Astrophysical Observatory
2021
Center for Astrophysics Harvard & Smithsonian
2021
University of California, Berkeley
2019
Identifying PAHs in space Midinfrared spectroscopy has shown that polycyclic aromatic hydrocarbons (PAHs) are abundant many astronomical objects, but this technique cannot determine which specific PAH molecules present. Radio astronomy could provide individual identifications if the molecule is sufficiently and a large dipole moment, expected to produce numbers of very weak lines. McGuire et al. performed stacking matched filter analysis search for radio observations TMC-1, located within...
We present laboratory rotational spectroscopy of five isomers cyanoindene (2-, 4-, 5-, 6-, and 7-cyanoindene) using a cavity Fourier-transform microwave spectrometer operating between 6-40 GHz. Based on these measurements, we report the detection 2-cyanoindene (1H-indene-2-carbonitrile; 2-C$_9$H$_7$CN) in GOTHAM line survey observations dark molecular cloud TMC-1 Green Bank Telescope at centimeter wavelengths. Using combination Markov Chain Monte Carlo (MCMC), spectral stacking, matched...
We have conducted an extensive search for nitrogen-, oxygen-, and sulfur-bearing heterocycles toward Taurus Molecular Cloud 1 (TMC-1) using the deep, broadband centimeter-wavelength spectral line survey of region from GOTHAM large project on Green Bank Telescope. Despite their ubiquity in terrestrial chemistry, confirmed presence a number cyclic polycyclic hydrocarbon species source, we find no evidence any heterocyclic species. Here, report derived upper limits column densities these...
Abstract Using data from the Green Bank Telescope (GBT) Observations of TMC-1: Hunting for Aromatic Molecules (GOTHAM) survey, we report first astronomical detection C 10 H − anion. The observations also provided necessary to refine spectroscopic parameters . From velocity stacked and matched filter response, is detected at >9 σ confidence level a column density <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>4.04</mml:mn>...
Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent rings. Infrared emission bands show that PAHs abundant in space, but only a few specific have been detected the interstellar medium. We 1-cyanopyrene, cyano-substituted derivative of related four-ring PAH pyrene, radio observations dense cloud TMC-1, using Green Bank Telescope. The measured column density 1-cyanopyrene is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"...
Abstract We report observations of the Didymos–Dimorphos binary asteroid system using Atacama Large Millimeter/submillimeter Array (ALMA) and Compact (ACA) in support Double Asteroid Redirection Test mission. Our on UT 2022 September 15 provided a preimpact baseline first measure Didymos–Dimorphos’s spectral emissivity at λ = 0.87 mm, which was consistent with handful siliceous carbonaceous asteroids measured millimeter wavelengths. postimpact were conducted four consecutive executions each...
Abstract Binaries are known to play a key role in the mass loss and dynamical environments of evolved stars. Stellar substellar companion interactions produce complex wind morphologies including rotating/expanding disks, bipolar outflows, spiral patterns; however, connection between these many structures gas-phase chemistry they harbor is not well constrained. To expand sample chemical inventories interacting systems, we present detailed spectroscopic case study binary C-rich asymptotic...
Context. The chemical pathways linking the small organic molecules commonly observed in molecular clouds to large, complex, polycyclic species long suspected of being carriers ubiquitous unidentified infrared emission bands remain unclear. Aims. To investigate whether formation mono- and cold cores could form via bottom-up reaction carbon-chain with, for example, atomic hydrogen, a search is made possible intermediates data taken as part GOTHAM (GBT Observations TMC-1: Hunting Aromatic...
We report the discovery of two unsaturated organic species, trans-(E)-cyanovinylacetylene and vinylcyanoacetylene, using second data release GOTHAM deep survey towards TMC-1 with 100 m Green Bank Telescope. For both detections, we performed velocity stacking matched filter analyses Markov chain Monte Carlo simulations, for trans-(E)-cyanovinylacetylene, three rotational lines were observed at low signal-to-noise (${\sim}$3$\sigma$). From this analysis, derive column densities...
We report a systematic study of all known methyl carbon chains toward TMC-1 using the second data release GOTHAM survey, as well search for larger species. Using Markov-Chain Monte Carlo simulations and spectral line stacking over 30 rotational transitions, we statistically significant emission from methylcyanotriacetylene (CH$_3$C$_7$N) at confidence level 4.6$\sigma$, use it to derive column density ${\sim}$10$^{11}$ cm$^{-2}$. also searched related species, methyltetraacetylene...
Abstract In recent years, many questions have arisen regarding the chemistry of photochemical products in carbon-rich winds evolved stars. To address them, it is imperative to constrain distributions such species through high-angular-resolution interferometric observations covering multiple rotational transitions. We used archival Atacama Large Millimeter/submillimeter Array map lines involving high energy levels cyanoacetylene (HC 3 N) toward inner envelope (radius < 8″/1000 au) carbon...
Thioacetamide (CH3CSNH2) is the sulfur analog to acetamide (CH3CONH2) and it a viable candidate search for in astronomical environments specifically toward regions where other S-bearing molecules have been found and, if possible, that also contain detection of CH3CONH2. If detected, would not only continue expand view molecular complexity environments, but help better elucidate possible formation pathways these types species environments. The rotational spectrum CH3CSNH2 was investigated up...
Abstract We report a search for the diatomic hydrides SiH, PH, and FeH along line of sight toward chemically rich circumstellar envelopes IRC+10216 VY Canis Majoris. These molecules are thought to form in high-temperature regions near photospheres those stars, may then further react via gas-phase dust-grain interactions leading more complex species, but have yet be constrained by observation. used German Receiver Astronomy at Terahertz Frequencies spectrometer on Stratospheric Observatory...
Polycyclic aromatic hydrocarbons (PAHs) are expected to be the most abundant class of organic molecules in space. Their interstellar lifecycle is not well understood, and progress hampered by difficulties detecting individual PAH molecules. Here, we present discovery CN-functionalized pyrene, a 4-ring PAH, dense cloud TMC-1 using 100-m Green Bank Telescope. We derive an abundance 1-cyanopyrene ~1.52 x $10^{12}$ cm$^{-2}$, from this estimate that un-substituted pyrene accounts for up...
Binaries are known to play a key role in the mass loss and dynamical environments of evolved stars. Stellar sub-stellar companion interactions produce complex wind morphologies including rotating/expanding disks, bipolar outflows, spiral patterns; however, connection between these many structures gas phase chemistry they harbor is not well-constrained. To expand sample chemical inventories interacting systems, we present detailed spectroscopic case study binary C-rich Asymptotic Giant Branch...
Using data from the GOTHAM (GBT Observations of TMC-1: Hunting for Aromatic Molecules) survey, we report first astronomical detection C10H- anion. The observations also provided necessary to refine spectroscopic parameters C10H-. From velocity stacked and matched filter response, is detected at >9σ confidence level a column density 4.04e11 cm-2. A dedicated search C10H radical was conducted towards TMC-1. In this case, molecular emission ~3.2σ interval 2.02e11 However, since determined...
We report observations of the Didymos-Dimorphos binary asteroid system using Atacama Large Millimeter/Submillimeter Array (ALMA) and Compact (ACA) in support Double Asteroid Redirection Test (DART) mission. Our on UT 2022 September 15 provided a pre-impact baseline first measure Didymos-Dimorphos' spectral emissivity at $\lambda=0.87$ mm, which was consistent with handful siliceous carbonaceous asteroids measured millimeter wavelengths. post-impact were conducted four consecutive executions...
We present laboratory rotational spectroscopy of five isomers cyanoindene (2-, 4-, 5-, 6-, and 7-cyanoindene) using a cavity Fourier-transform microwave spectrometer operating between 6-40 GHz. Based on these measurements, we report the detection 2-cyanoindene (1H-indene-2-carbonitrile; 2-C$_9$H$_7$CN) in GOTHAM line survey observations dark molecular cloud TMC-1 Green Bank Telescope at centimeter wavelengths. Using combination Markov Chain Monte Carlo (MCMC), spectral stacking, matched...
In recent years, many questions have arisen regarding the chemistry of photochemical products in carbon-rich winds evolved stars. To address them, it is imperative to constrain distributions such species through high angular resolution interferometric observations covering multiple rotational transitions. We used archival ALMA map lines involving energy levels cyanoacetylene (HC$_3$N) toward inner envelope (radius <8"/1000 AU) carbon star IRC+10216. The observed include J=28-27, J=30-29,...
The chemical pathways linking the small organic molecules commonly observed in molecular clouds to large, complex, polycyclic species long-suspected be carriers of ubiquitous unidentified infrared emission bands remain unclear. To investigate whether formation mono- and poly-cyclic cold cores could form via bottom-up reaction carbon-chain with, e.g. atomic hydrogen, a search is made for possible intermediates data taken as part GOTHAM (GBT Observations TMC-1 Hunting Aromatic Molecules)...
V510 Pup (IRAS 08005-2356) is a binary post-AGB system with fast molecular outflow that has been noted for its puzzling mixture of carbon- and oxygen-rich features in the optical infrared. To explore this chemical dichotomy relate it to kinematics source, we present an ACA spectral line survey detailing fourteen newly detected molecules pre-planetary nebula. The simultaneous presence CN/C2H/HC3N SO/SO2 support previous conclusion mixed chemistry, their profiles indicate C- O-rich material...